IACS UR S35 Plate Buckling (2023)

IACS UR S35 Plate Buckling (2023) standard implementation according to IACS UR S35 Buckling Strength Assessment of Ship Structural Elements, February 2023 (Corr. 1 Sep. 2024).

IACS UR S35 Plate Buckling (2023)

To add the Standard execute Standards - Main - Other - IACS UR S35 Plate Buckling (2023) from the ribbon:

Plate Buckling Checks are calculated on Sections. With the help of Panel Finder tool, it is possible to automatically recognize Section and Plates with their dimensions.

By default, All Sections are included in the selection but it can be changed by pressing . If sections were not recognized press to run Panel Finder tool.

Press to Set Standard Custom Settings

Standard uses material data (Yield/Tensile) in calculations. Wizard checks if the values are defined for all materials.

Options

Assessment Method - Section 1 / [3.1] - Assessment Methods.

Thickness Factor - increases each plate thickness (e.g. 1.1 increase on 10%) and decreases stresses;

Partial Safety Factor - S = 1.0, unless otherwise specified in Relevant UR-S (Sec. 5 / Symbols);

Use Plate Average Stress - use average element stress if OFF or averaged stress on the plate using elements area if ON;

Stress on Element - Element Stress Results to use in calculations (Maximum Compression or Average);

Include Plate Dimensions in the table - set parameters Length, Width and Thickness to be included in the table.

Plate Buckling Results

• Criteria Plot
• Table (Expand/Extreme)
• Flow table (over loads)

Stress Conversion

Plate Buckling check requires to verify element stresses (Sx, Sy and Txy) to be translated into the plate X, Y, XY directions.

Conversion of the stresses is done automatically in Plate Buckling check. If Use Plate Average Stress option is turned OFF (by meaning element average option is used) - the nodal element stresses at top and bottom are averaged (which is equivalent to using midplane centroid stress) and translated into plate directions.

SDC Verifier makes an assumption that the plate elements are calculated without any output transformation and the default values are used:

• For triangle elements x stress is oriented along the first ege (node1 -> node2 define 1 edge).
• For quad elements x stress is oriented along the Diagonal Bisector:

Plate Dimensions and Thickness

Results depend on the plate dimensions and direction. It is important to understand how the Panel Finder performs recognition. Length is considered to be the longest edge of the plate and width the longest perpendicular to the longest edge:

Plate dimentions can be calculated using CSR method - calculate equivalent rectangular plate dimensions described in Common Structural Rules (1 Jan 2018) Part 1, Chapter 8, Section 4 (2.3)

Calculations are performed on every element and thickness is taken directly from each element. It is possible to set thickness manually, in this case, element thickness will be ignored and user-defined thickness will be used.

Example: A Plate with 2 properties 0.01 and 0.02 thicknesses. The left picture displays the property labels with property thicknesses and the right one presents plate buckling plot of thickness parameter: